1. Field of the Invention
The present invention relates to a scanner printer server system constituted by connecting a integrated type scanner printer to a network.
2. Description of the Prior Art
Hitherto, a sole scanner or a printer has been used in such a manner that it has been directly connected to the host computer. On the other hand, an integrated type scanner printer has been usually used solely as a copying machine and the scanner or the printer of the above-described type has not been used as a scanner printer server while being connected to a network.
On the other hand, there has been used a structure in which a printer is commonly used while being connected to a printer server on a network. In the usual case, a printer server of the aforesaid type transfers data adaptable to the specifications of the printer from the host computer to the printer.
Recently, network systems have been widely used and a large scale network has been employed in which the LAN is arranged in the overall context of an intelligent building or the like for example. Furthermore, a nationwide network such as WAN (wide area network) in which the LAN is directly connected by public lines and an advanced information network such as ISDN have become available.
Therefore, it has been possible for a host computer on one floor in one building to be utilized from another floor of the building or from another building, or a host computer located in Osaka can be utilized from Tokyo.
Therefore, the printer server should become available for use in a very wide region as well as in a relatively narrow area, which has been so far achieved.
Furthermore, the scanner printer has been advanced in function and resolution, and color scanner printers have become available. Therefore, data can be read from various scanners so as to be transmitted to the printer.
The method of transferring an image has generally been set by a host computer directly connected to the scanner or the printer.
On the other hand, a system so arranged that the scanner and the printer are both connected to the network will enable a user to utilize a distant scanner and printer by using the host computer located on the network.
This is very effective because a plurality of users are then able to utilize the distant scanner and the printer from a plurality of host computers.
In order to perform communication between the host computer and the scanner printer server, each layer of the control/programming hierarchy must be aligned with its corresponding layer across the communication channel. The layers may be those as shown in FIG. 20:
1) Page description language (PDL) such a PostScript or CaPSL PA1 2) Image encoding method such as ADCT, MMR, MR, VQ (Vector Quantizing) PA1 3) Format such as a dot sequential, line sequential, or plane sequential method (interleaving) PA1 4) Color space such as RGB, Lab, or YIQ PA1 5) Number of gradations expressed by 1, 2, . . . , 8 bits/Color PA1 6) Size and position of the image (trimming) PA1 7) Resolution expressed by 100 dpi, 200 dpi or 400 dpi, or the like
In a case of a scanner printer server to which a plurality of scanners and printers or an integrated scanner printer is connected, the process to be performed by the server before the transmission of data has varied due to the differences in the performance of their I/O devices.
In the usual case, priority is given to the fact that scanning or printing is performed in the form required by a user of the host computer. Therefore, the scanner printer side has a variety of conversion means to scan or print data in the form required by the user.
Hence, the parameters for the distant scanner or the printer for use at the time of the various conversions must be set from the host computer.